A single dose of the SARS-CoV-2 vaccine BNT162b2 elicits Fc-mediated antibody effector functions and T cell responses

• Published in: Cell host & microbe 2021-07, Vol.29 (7), p.1137-1150.e6
• Main Authors: Tauzin, Alexandra, Nayrac, Manon, Benlarbi, Mehdi, Gong, Shang Yu, Gasser, Romain, Beaudoin-Bussières, Guillaume, Brassard, Nathalie, Laumaea, Annemarie, Vézina, Dani, Prévost, Jérémie, Anand, Sai Priya, Bourassa, Catherine, Gendron-Lepage, Gabrielle, Medjahed, Halima, Goyette, Guillaume, Niessl, Julia, Tastet, Olivier, Gokool, Laurie, Morrisseau, Chantal, Arlotto, Pascale, Stamatatos, Leonidas, McGuire, Andrew T., Larochelle, Catherine, Uchil, Pradeep, Lu, Maolin, Mothes, Walther, De Serres, Gaston, Moreira, Sandrine, Roger, Michel, Richard, Jonathan, Martel-Laferrière, Valérie, Duerr, Ralf, Tremblay, Cécile, Kaufmann, Daniel E., Finzi, Andrés
• Format: Article
• Language: English
• Subjects: ADCC; Adult; Antibodies, Neutralizing - immunology; Antibodies, Viral - chemistry; Antibodies, Viral - immunology; Betacoronavirus; BNT162 Vaccine; Carrier Proteins; coronavirus; COVID-19; COVID-19 - immunology; COVID-19 - prevention & control; COVID-19 Vaccines - administration & dosage; COVID-19 Vaccines - immunology; Female; Humans; humoral responses; Immunity; Immunoglobulin Fc Fragments; Male; Middle Aged; mRNA vaccine; mRNA Vaccines; neutralization; SARS-CoV-2; SARS-CoV-2 - immunology; spike glycoproteins; T cell responses; T-Lymphocytes - immunology; Vaccination; Vaccines, Synthetic - immunology; variants; Young Adult
• ISSN: 1931-3128; 1934-6069
• DOI: 10.1016/j.chom.2021.06.001

While the standard regimen of the BNT162b2 mRNA vaccine for SARS-CoV-2 includes two doses administered 3 weeks apart, some public health authorities are spacing these doses, raising concerns about efficacy. However, data indicate that a single dose can be up to 90% effective starting 14 days post-administration. To assess the mechanisms contributing to protection, we analyzed humoral and T cell responses three weeks after a single BNT162b2 dose. We observed weak neutralizing activity elicited in SARS-CoV-2 naive individuals but strong anti-receptor binding domain and spike antibodies with Fc-mediated effector functions and cellular CD4+ T cell responses. In previously infected individuals, a single dose boosted all humoral and T cell responses, with strong correlations between T helper and antibody immunity. Our results highlight the potential role of Fc-mediated effector functions and T cell responses in vaccine efficacy. They also provide support for spacing doses to vaccinate more individuals in conditions of vaccine scarcity. [Display omitted] •Three weeks after the first BNT162b2 dose, weak neutralizing antibodies are elicited•These antibodies have robust Fc-mediated effector functions•Vaccination of individuals previously infected boosts humoral and cellular responses•Strong correlations between T helper cell and humoral responses are observed Tauzin and Nayrac et al. characterize humoral and cellular responses 3 weeks after a single dose of mRNA BNT162b2 vaccine. They show, in SARS-CoV-2-naive individuals, that the antibodies elicited have weak neutralizing activity but potent Fc-mediated effector functions, and in SARS-CoV-2 previously infected individuals, that all responses are significantly boosted.